Tumbler switches



Dec. 4, 1962 MITITAKA YAMAMOTO TUMBLER SWITCHES Fiied Feb. 26. 1960 INVENTOR Mititaka Yamamoto W TTRNEY United States Patent O 3,067,301 TUMBLER SWTCHES Mititaka Yamanoto, 17 Gotandacho, Ryuanji, Ukyoku, Kyoto, Japan Filed Feb. 26, 1960, Ser. No. 11,211 3 Claims. (Cl. 200-67) This invention relates to tumbler switches of small, compact precision type.

The Object of the invention includes the provision of an improved compact electric snap switch which is simple and economical in construction, easily assembled, and reliable and precise in operation. This type of switch operates in response to slight motion and pressure.

The invention will be better understood as reference is made in the following description to the accompanying drawings, in which FIG. 1 is a side view of the thin leaf spring constituting the snap member of the tumbler switches according to this invention,

FIG. 2. is a plan view of the same,

FIG. 3 is a sectional view of the tumbler switch,

FIG. 4 is a sectional view of a modification, and

FIG. 5 is a side view of the other modification.

The snap member 1 employed in the tumbler switches according to this invention consists of a thin leaf spring, a portion (BC) thereof being bent at an obtuse angle (O) to the remaining portion (AB) and compressed to a bow shape (BEC) to store up the energy to snap. A movable double faced contact 9 is attached to the unbent portion (AB).

In the tumbler switch shown in FIG. 3, 2 is a case of molded, arc resisting, insulating material, 6 is a swing piece of insulating material pivoted at 7 within the opening 5 formed in the case 2, 1 is a snap member as shown in FIGS. `1 -and 2, one end of which being fixed to a terminal 26 while the other end of the bow shaped portion is disposed in a recess 8 formed in the inner side of the swing piece 6. 10 and \11 are station-ary contacts arranged to cooperate with the movable contact 9 attached to the leaf spring 1.

The operation of this tumbler switch is as follows: In the drawing, the movable contact 9 is shown in contact with the stationary contact 11 and the swing piece 6 inclined to the right. DoWnwar-d pressure is now exerted on the left side of the swing piece 6 and pivotal movement of the swing piece 6 causes the increase of the compression as well as an increase in the curvature of the bow shaped portion of the leaf spring until the leaf spring snaps suddenly from the position shown in full line to the dotted line position whereby the movable contact 9 is brought into contact with the other stationary contact 10.

The swing of the piece 6 is limited by shoulders 3 and 4 formed in the case 2.

As is well understood, the snap member 1 is simple but very Sensitive to respond to slight motion and pressure. Further, electric current flows through only the portion between the end (A) and the movable contact 9 but not through the bow shaped portion whereby the delicate curved portion of the leaf spring is effectively kept from the effect of the heat generated by electricity. Due to the arrangement of the spring 'member 1, the curvature in the area between B and C never reverses "ice itself, but always curves in the same direction. As a result, a loss of springiness does not occur to the extent which takes place With curved Springs often used in switches and with which a reversal of curvature occurs during movement of the spring from one position to the other. Moreover, the range of movement of the described spring member is relatively small and as a result a switch incorporating the present improvements can be made much smaller than can many of the switches in which Springs that require a reversal of curvature are used.

-In a modification shown in FIG. 4, the housing has a body *12 and a cover 13 seated over the body. Through said cover, two reciprocating plungers 14 and `15 are inserted, each of said plungers abutting on each side of the swing piece 16 pivoted at 17 within the body. The base of the swing piece 16 is provided with an anchor 18 which engages with the end of the bow shaped portion of the leaf spring 1. The function of this tumbler switch will be self-evident; i.e. by depressing the plungers 14 and 15 alternately, the movable contact 9 will be brought into contact in turn with the stationary contacts lt) or 11.

In the other modification shown in FIG. 5, a swing piece 20 of a T-form is pivoted at 22 in the case 19. At the inner end of the T piece 20, an anchor 23 and an L-shaped piece 24 are fixed. The anchor 23 engages l the end of the bow shaped portion of the leaf spring 1 while the L-shaped piece 24 abuts on a himetal 25.

The function of this tumbler switch is as follows: By temperature rise, the himetal 25 will warp to the left whereby the piece 20 is forced to swing to the right causing the leaf spring to snap.

Not only is this tumbler switch operated thermally as mentioned above, but also it can be operated manually.

Having thus described the invention, what is claimed as new is:

1. Tumbler switch comprising a case, a swing piece pivoted to the case, two reciproc-ating plungers inserted through the cover of said case, the lower ends of said plungers abutting on the sides of a swing piece, a snap member consisting of a thin leaf spring, a portion thereof being bent at an obtuse angle to the remaining part and compressed .to a bow shape and always remaining bowed in the same direction, the end of said compressed portion being engaged by an anchor fixed at the inner surface of the swing piece, the engagement of the end of the compressed portion With said anchor tending to maintain the bow shaped part under compression and in such bow shape and stationary contacts to cooperate with the novable contacts carried by the snap member.

2. Tumbler switch comprising a case of insulating material, a swing piece pivoted to the case, a snap member consisting of a thin leaf spring, a portion thereof being bent at an obtuse angle to the remaining part and compressed to a bow shape, an anchor fixed to the swing piece to engage with the end of the bow shaped portion of the leaf spring, the engagement of the end of the compressed portion with said anchor tending to maintain the bow shaped part under compression and in such bow shape, and an L-shaped piece fixed also to the swing piece on -a himetal strip within the case, said L- shaped piece abutting against the himetal strip, and stationary contacts arranged to cooperate with the movable contact carried by the leaf spring.

3. A tumbler switch comprising, a case composed of insulating material, a swing piece pivoted to the case, a snap member consisting of a thin leaf spring, a portion thereof being bent at an obtuse angle to the remainder of the spring, and being in a compressed boW shape and always remaining bowed in the same direction, one end of said compressed bow shaped portion being engaged by the swing piece and the other end of said bow shaped portion being fixed to the case, spaced stationary contacts, and movable contacts attached to the straight and unbowed portion of the spring and adapte-d for contact With one or the other of the spaced contacts.

References Cited in the file of this patent UNITED STATES PATENTS Klein Aug. 21, 1906 Klein Oct. 10, 1922 Thomas May 3, 1932 Arnold Oct. 10, 1933 Sargrove July 5, 1949 Green Nov. 13, 195 1 Xenakis Oct. 8, 1957 Edwards July 8, 1958 Nelson Feb. 2, 1960 

